气候变化领域集成服务门户(CCPortal): Mantle Heterogeneity and Melting Processes in the South China Sea: Thermal and Melting Models Constrained by Oceanic Crustal Thickness and Basalt Geochemistry

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DOI	10.1029/2020JB020735
	Mantle Heterogeneity and Melting Processes in the South China Sea: Thermal and Melting Models Constrained by Oceanic Crustal Thickness and Basalt Geochemistry
	Zhang X.; Lin J.; Behn M.D.
发表日期	2021
ISSN	21699313
卷号	126 期号:2
英文摘要	We simulate mantle flow, thermal structure, and melting processes beneath the ridge axis of the South China Sea (SCS), combining the nominally anhydrous melting and fractional crystallization model, to study mantle heterogeneity and basin evolution. The model results are constrained by seismically determined crustal thickness and major element composition of fossil ridge axis basalts. The effects of half-spreading rate, mantle potential temperature, mantle source composition, and the pattern of melt migration on the crustal thickness and magma chemical composition are systematically investigated. For the SCS, the east and southwest (SW) subbasins have comparable crustal thickness, but the east subbasin has higher FeO and Na2O contents compared to the SW subbasin. The estimated best fitting mantle potential temperatures in the east and SW subbasins are 1,360 ± 15 °C and 1,350 ± 25 °C, respectively. The mantle in the east subbasin (site U1431) prior to the cessation of seafloor spreading is composed primarily of the depleted mid-ocean ridge basalt mantle (DMM), and is slightly contaminated by eclogite/pyroxenite-rich component. However, the mantle source composition of the SW subbasin (sites U1433 and U1434) contains a small percentage (2–5%) of lower continental crust. Basalt samples at the northern margin of the east subbasin (site U1500) shows similar chemical characteristics with that of the SW subbasin. We suggest that the basin-scale variability in the mantle heterogeneity of the SCS can be explained by a single model in which the contamination by the lower continental crust is gradually diluted by melting of DMM as the ridge moves away from the rifted margin. © 2021. American Geophysical Union. All Rights Reserved.
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187350
作者单位	Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China; Southern Marine Science and Engineering, Guangdong Laboratory (Guangzhou), Guangzhou, China; China-Pakistan Joint Research Center on Earth Sciences, CAS-HEC, Islamabad, Pakistan; State Key Laboratory of Marine Geology, School of Ocean and Earth Science, Tongji University, Shanghai, China; Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, United States; Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China; Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, MA, United States
推荐引用方式 GB/T 7714	Zhang X.,Lin J.,Behn M.D.. Mantle Heterogeneity and Melting Processes in the South China Sea: Thermal and Melting Models Constrained by Oceanic Crustal Thickness and Basalt Geochemistry[J],2021,126(2).
APA	Zhang X.,Lin J.,&Behn M.D..(2021).Mantle Heterogeneity and Melting Processes in the South China Sea: Thermal and Melting Models Constrained by Oceanic Crustal Thickness and Basalt Geochemistry.Journal of Geophysical Research: Solid Earth,126(2).
MLA	Zhang X.,et al."Mantle Heterogeneity and Melting Processes in the South China Sea: Thermal and Melting Models Constrained by Oceanic Crustal Thickness and Basalt Geochemistry".Journal of Geophysical Research: Solid Earth 126.2(2021).